CN105088191B - The fluid control features structure of CVD chambers - Google Patents

Abstract

The present invention relates to a fluid control feature for a CVD chamber. The present invention provides apparatus and methods for gas distribution assemblies. In one aspect, there is provided a gas distribution assembly comprising: an annular body comprising: an annular ring having an inner annular wall, an outer wall, an upper surface and a bottom surface; an upper recess formed into the upper surface; and a seat formed into the inner annular wall; an upper plate disposed in the upper recess and comprising: a disc-shaped body having a plurality of first perforations formed therethrough; and a bottom plate disposed in the upper recess on the seat and comprising: a disc-shaped body having a plurality of second through-holes formed therethrough, the second through-holes being aligned with the first through-holes; and a plurality of third through-holes formed in the second through-holes Between and through the bottom plate, the bottom plate is sealingly connected to the upper plate to fluidly isolate the plurality of first and second through-holes from the plurality of third through-holes.

Description

Fluid Control Features for CVD Chambers

technical field

The present invention relates to apparatus for processing substrates, such as semiconductor substrates, and more particularly to apparatus for distributing process fluids over substrates.

Background technique

Semiconductor process systems generally include a process chamber having a susceptor for supporting a substrate, such as a semiconductor substrate, adjacent a process area within the chamber. The chamber forms a vacuum volume that partially defines the process area. A gas distribution assembly or showerhead provides one or more process gases to the process area. These gases are then heated and/or energized to form a plasma, which performs a specific process on the substrate. These processes may include deposition processes such as chemical vapor deposition (CVD) to deposit material on the substrate, or etching reactions to remove material from the substrate, or other processes.

In processes requiring multiple gases, these gases may be combined in a mixing chamber which in turn is connected to the gas distribution assembly via conduits. For example, in a conventional thermal CVD process, two process gases, together with two corresponding carrier gases, are supplied to a mixing chamber where they are combined to form a gas mixture. The gas mixture can be introduced directly into the chamber, or run through a conduit in the upper part of the chamber to the dispersion assembly. The distribution assembly generally includes a plate with a plurality of holes so that the gas mixture is evenly distributed into the process area above the substrate. In another example, the two gases pass through the distribution assembly separately and are allowed to combine before reaching the process area and/or substrate. As the gas mixture enters the process area and is injected with thermal energy, a chemical reaction occurs between these process gases resulting in a chemical vapor deposition reaction on the substrate.

Although it is generally beneficial to mix the gases prior to release into the process area, eg, to ensure that the constituent gases are evenly dispersed into the process area, these gases tend to start reducing or reacting within the mixing chamber or distribution plate. Therefore, before the gas mixture reaches the process area, deposition or etching on etch chambers, conduits, diffuser plates and other chamber components can result. In addition, reaction by-products can build up in the chamber gas delivery components or on the interior surfaces of the distribution plate, thereby creating and/or increasing the presence of undesirable particulates.

Temperature control of the gas is beneficial to control the reactivity of the gas as it is released into the process area. For example, cooling these gases helps control undesired reactions before they are released into the process area. These gases are prevented from reacting until they contact the heated substrate. In other cases, heating of these gases is necessary. For example, hot gas purge or cleaning helps remove contaminants from process chambers. Therefore, it is useful to incorporate a temperature control aspect into the gas distribution plate.

Therefore, there continues to be a need for a gas distribution device that delivers at least two gases into a process area without mixing before the gases reach the process area.

Contents of the invention

Aspects described herein relate to an apparatus for delivering a process fluid, such as a gas, to a process chamber for depositing a film on a substrate or for other processes. In one aspect, there is provided a gas distribution assembly comprising: a first manifold having a plurality of first perforations formed therethrough for passage of a first fluid, and the first manifold defines a A flow path for a second fluid; and a second manifold, the top side of which is connected to the first manifold and isolates the flow path from the first fluid, and the second manifold has a plurality of second perforations and a plurality of A third perforation, each second perforation connected to one of the first perforations, the plurality of third perforations fluidly connected to the flow path.

In another aspect, a gas distribution assembly is provided comprising: an upper manifold comprising: a plurality of first perforations formed as a plurality of first radial rows concentrically disposed about a central portion of the upper manifold , and a plurality of second perforations disposed concentrically around the first plurality of perforations and formed in a plurality of second radial rows; a central manifold connected to the upper manifold and comprising: a first set of openings , which is concentrically disposed about the central portion of the central manifold, and a second set of openings, which is concentrically disposed about the first set of openings; and a bottom manifold, which is connected to the central manifold and comprises: A third group of openings is concentrically disposed around the central portion of the bottom manifold, a fourth group of openings is concentrically disposed around the third group of openings, a plurality of first gas channels are disposed on the bottom Between each of the fourth openings on the upper side of the manifold, and a network of channels disposed concentrically around the set of fourth openings and fluidly connected to one or more of the first gas channels.

Description of drawings

It is to be noted, however, that the appended drawings illustrate only typical embodiments of this invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments. Even so, the teachings of the present invention can be readily appreciated by considering the following detailed description and accompanying drawings, in which:

Figure 1 is a top view of one embodiment of a process tool;

2A-2C are schematic cross-sectional views of one embodiment of a process chamber;

3A-3M are schematic diagrams of one embodiment of a gas distribution assembly described herein;

4A-4I are schematic illustrations of one embodiment of a gas distribution assembly described herein;

5A-5F are schematic illustrations of one embodiment of a gas distribution assembly described herein.

For ease of understanding, the same reference numerals have been used, where possible, to designate the same components in the various figures. That is, components disclosed in one embodiment can also be beneficially used in other embodiments without specific specification.

Detailed ways

Aspects described herein relate to an apparatus for delivering a process fluid to a process chamber for depositing a film on a substrate or for other processes.

FIG. 1 is a top view of an embodiment of a process tool 100 having deposition, baking and curing chambers in accordance with disclosed embodiments. In the figure, a pair of FOUPs (front opening unified pods) 102 supply substrates (e.g. 300mm diameter substrates) which are processed in substrates placed into series process chambers 109a-c One of the sections 108a - f was previously received by the robotic arm 104 and placed within the lower chamber holding area 106 . The second robotic arm 110 may be used to transfer the substrate from the holding area 106 to the process chambers 108a-f and back.

The substrate processing sections 108a-f of the series process chambers 109a-c may include one or more system components for depositing, annealing, curing, and/or etching flowable dielectric films on substrates. In one configuration, two pairs of in-line processing sections of a process chamber (eg, 108c-d and 108e-f) may be used to deposit flowable dielectric material on a substrate, and a third pair of in-line processing sections (eg, 108a-b) to anneal the deposited dielectric. In another configuration, two pairs of in-line processing sections of the process chamber (eg, 108c-d and 108e-f) may be configured to deposit and anneal flowable dielectric films on substrates, while the third pair of in-line processing sections (eg 108a-b) can be used for UV or e-beam hardening of the deposited film. In yet another configuration, all three pairs of serial processing sections (eg, 108a-f) may be configured to deposit and harden a flowable dielectric film on a substrate.

In yet another configuration, two pairs of serial processing sections (eg, 108c-d and 108e-f) can be used for deposition and UV or electron beam hardening of flowable dielectrics, while a third pair of serial processing sections (eg, 108a-b) can be used for annealing the dielectric film. It will be appreciated that system 100 includes additional structures for deposition, annealing and hardening chambers for flowable interfacial films.

Additionally, one or more in-line processing sections 108a-f may be configured as wet processing chambers. These process chambers include heating the flowable dielectric film in an atmosphere that includes moisture. Accordingly, embodiments of the system 100 may include wet processing tandem processing sections 108a-b and annealing tandem processing sections 108c-d to perform wet and dry anneals on the deposited dielectric film.

2A is a cross-sectional view of an embodiment of a process chamber portion 200 having multiple separate plasma generation regions within a tandem process chamber. During film deposition (silicon oxide, silicon nitride, silicon oxynitride, or silicon oxycarbide), process gases may flow through the gas inlet assembly 205 into the first plasma region 215 . The process gas may be excited within a remote plasma system (RPS) 201 before entering the first plasma region 215 . Cap 212, showerhead 225, and substrate support 265 on which substrate 255 is disposed are shown, according to the disclosed embodiment. Cap 212 may be pyramidal, conical, or other similar structure having a narrow top flared to a wide base. Cover 212 is shown with an AC voltage source applied, and showerhead grounded, consistent with plasma generation in first plasma region 215 . The insulating ring 220 is positioned between the cap 212 and the showerhead 225 such that a capacitively coupled plasma (CCP) is formed in the first plasma region.

According to disclosed embodiments, cover 212 may be a dual source cover for a process chamber. Fluid inlet assembly 205 introduces a fluid, such as a gas, into first plasma region 215 . Two distinct fluid supply channels can be seen within fluid inlet assembly 205 . A first channel 202 carries a fluid (such as a gas) through the remote plasma system RPS 201 , while a second channel 204 has a fluid (such as a gas) that bypasses the RPS 201 . In the disclosed embodiment, the first channel 202 may be used for process gas and the second channel 204 may be used for process gas. These gases may flow into the plasma region 215 and be dispersed by the baffle 206 . It is shown that there is an insulating ring 220 between the cap 212 and the showerhead 225 which allows an AC potential to be applied to the cap 212 relative to the showerhead 225 .

Fluids, such as precursors, eg, silicon-containing precursors, may flow through embodiments of the showerhead described herein into the second plasma region. The excited species obtained from the process gas in the plasma region 215 travels through the perforations in the showerhead 225 and reacts with the precursors flowing from the showerhead into the second plasma region 233 . Little or no plasma exists in the second plasma region 233 . The process gas and the excited derivatives of the precursors combine in the region above and sometimes on the substrate to form a flowable film on the substrate. As the film grows, more recently added material has higher mobility than underlying material. Reduced mobility due to reduction of organic content by evaporation. Gaps can be filled by this technique with flowable films without leaving conventional organic content densities in the film after deposition is complete. A hardening step can still be used to further reduce or remove the organic content from the deposited film.

Exciting the process gas directly in the first plasma region 215, in a remote plasma system (RPS), or both may provide some advantages. The concentration of excited species induced from the process gas may be increased in the second plasma region 233 due to the plasma in the first plasma region 215 . This increase may be due to the location of the plasma in the first plasma region 215 . The second plasma region 233 is closer to the first plasma region 215 than the remote plasma system (RPS) 201 , so that excited species spend less time away from the excited state through collisions with other gas molecules, chamber walls, and showerhead surfaces.

The uniformity of the concentration of excited species induced from the process gas may also be increased within the second plasma region 233 . This may be due to the shape of the first plasma region 215 (which is more similar to the shape of the second plasma region 233). Excited species generated in remote plasma system (RPS) 201 travel a greater distance for passing through perforations near the edge of showerhead 225 relative to species passing through perforations near the center of showerhead 225 . Greater distances result in reduced excitation of excited species and, for example, may result in slower growth rates near the edges of the substrate. Exciting the process gas in the first plasma region 215 mitigates this variation.

Preferably, the process gas is energized in the RPS 201 and passed through the showerhead 225 to the second plasma region 233 in an energized state. Alternatively, power may be applied to the first process region to energize the plasma gas or enhance the energized process gas from the RPS. Although plasma may be generated in the second plasma region 233, in a preferred embodiment of the process, no plasma is generated in the second plasma region. In a preferred embodiment of the process, the excitation of the process gas or precursor comes only from energizing the process gas in the RPS 201 to react with the precursor in the second plasma region 233 .

Process chambers and tools are described in more detail in U.S. Patent Application Serial No. 12/210,940, filed September 15, 2008, and U.S. Patent Application Serial No. 12/210,982, filed September 15, 2008, which are incorporated by reference and This document is incorporated by reference to the extent that it is not inconsistent with the claimed aspects and narratives of this document.

2B-2C are side views of embodiments of precursor flow processes in process chambers and gas distribution assemblies described herein. The gas distribution assembly for process chamber section 200 is referred to as a dual zone showerhead (DZSH), and is shown in more detail in the embodiments described in FIGS. 3A-3K , 4A-4I , and 5A-5F. out. The gas flow description below relates broadly to the dual zone showerhead description and should not be construed or read as limiting on the showerhead aspects described herein. Although the following description refers to the deposition of dielectric materials, the inventors intend to demonstrate that the apparatus and method can be used to deposit other materials.

In one embodiment of the deposition process, a dual zone showerhead allows flowable deposition of dielectric material. Examples of dielectric materials that may be deposited in the process chamber include silicon oxide, silicon nitride, silicon oxycarbide, or silicon oxynitride. Silicon nitride materials include silicon nitride ( _Six N _y ), hydrogen-containing silicon nitride ( _Six N _y H _z ), silicon oxynitride (including hydrogen-containing silicon oxynitride, Six _{N y} H _{z Ozz} ), With halogen-containing silicon nitride (including silicon nitride chloride, _Six N _y H _z Cl _zz ). The deposited dielectric material can then be converted to a silicon oxide-like material.

The dielectric layer may be deposited by introducing a dielectric material precursor and reacting the precursor with a process gas in the second plasma region 233 or reaction space. Examples of precursors are silicon-containing precursors including silane, disilane, methylsilane, dimethylsilane, trimethylsilane, tetramethylsilane, tetraethoxysilane (TEOS), triethoxysilane ( TES), octamethylcyclotetrasiloxane (OMCTS), tetramethyldisiloxane (TMDSO), tetramethylcyclotetrasiloxane (TMCTS), tetramethyldiethoxydisiloxane alkane (TMDDSO), dimethyldimethoxysilane (DMDMS), or a combination of the above. Additional precursors for the deposition of silicon nitride include _SixNyHz -containing precursors such _{as silamine} and its derivatives, including trisiliconamine (TSA) and disilamine (DSA)), Si-containing A precursor of _x N _y H _z O _zz -, a precursor containing Six _{N y} H _z Cl _zz -, or a combination thereof.

The process gas includes hydrogen-containing compounds, oxygen-containing compounds, nitrogen-containing compounds, or combinations thereof. Examples of suitable gases include one or more compounds selected from the group consisting of: _H2 , _H2 / _N2 mixture, _NH3 , _NH4OH , _O3 , _O2 , _{H2O2 , N2} , _Nx H _y compound (including N ₂ H ₄ ) vapor, NO, N ₂ O, NO ₂ , water vapor, or a combination of the above. The process gas can be excited by a plasma (such as in an RPS unit) to include radicals or plasmas containing N ^* and/or H ^* and/or O ^* , such as _NH3 , _NH2 ^* , NH ^* , N ^* , H ^* , O ^* , N ^* O ^* , or a combination of the above. Alternatively, the process gas may include one or more precursors described herein.

The precursors are introduced into the reaction area by first introducing the first manifold 226 (or upper plate) and the second manifold 227 (or bottom plate) into the inner showerhead space 294 defined in the showerhead 225 . Precursors in the interior showerhead volume 294 flow 295 into the process region 233 via perforations 296 (openings) formed in the second manifold. This flow path is isolated from the rest of the process gas in the chamber and provides for the precursor to be in an unreacted or substantially unreacted state until it enters the process defined between the substrate 217 and the bottom of the second manifold 227 Area 233. Once the precursors are in the process region 233, the precursors may react with the process gas. The precursors may first be introduced into the interior showerhead volume 294 defined in the showerhead 225 via side channels formed in the showerhead, such as channels 490, 518, and (or 539) shown for the showerhead embodiments herein. The process gas may be in a plasma state, including radicals from the RPS or from a plasma generated in the first plasma region. In addition, plasma may be generated in the second plasma region.

The process gas may be provided into the first plasma region 215 or into the upper space bounded by the cap 212 and the top of the showerhead 225 . Dispersion of the process gas can be achieved through the use of a baffle 206, as shown in Figure 2A. The process gas may be plasma excited in the first plasma region 215 to create process gas plasmas and radicals, including radicals or plasmas containing N ^* and/or H ^* and/or O ^* , such as NH _{3. NH2} ^* , NH ^* , N ^* , H ^* , O ^* , N ^* O ^* , or a combination of the above. Alternatively, the process gas may already be in a plasma state after passing through the remote plasma system and before being introduced into the first plasma process region 215 .

Process gas 290 comprising plasma and radicals is then delivered to process region 233 via perforations 290, such as channels 290, for reaction with the precursors. When both the process gas and the precursor pass through the showerhead 255 , the process gas passing through the channel is physically isolated from the inner showerhead space 294 and will not react with the precursor passing through the inner showerhead space 294 . Once the process gas and precursor are in the process volume, the process gas and precursor may mix and react to deposit the dielectric material.

In addition to process gases and dielectric material precursors, other gases may be introduced at various points in time for various purposes. Process gases, such as hydrogen, carbon, and fluorine, may be introduced to remove undesired species from the chamber walls, the substrate, the deposited film, and/or the film during deposition. The process gas and/or process gas may comprise at least one of the following combinations of gases: H ₂ , H ₂ /N ₂ mixture, NH ₃ , NH ₄ OH, O ₃ , O ₂ , H ₂ O ₂ , N ₂ , N ₂ H ₄ vapor, NO, N ₂ O, NO ₂ , water vapor, or a combination of the above. Process gases can be excited in the plasma and then used to reduce or remove residual organic content from the deposited film. In other disclosed embodiments, process gases may be used in the absence of a plasma. When the process gas includes water vapor, delivery can be achieved using a mass flow meter (MFM), an injection valve, or through a commercially available water vapor generator. The process gas may be introduced into the first process region via the RPS unit or bypass the RPS unit, and the process gas may be further energized in the first plasma region.

The axis 292 of the opening of the through hole 291 and the axis 297 of the opening of the through hole 296 may be parallel or substantially parallel to each other. Alternatively, the axis 292 and the axis 297 may form an included angle with each other, such as 1° to 80°, eg 1° to 30°. Alternatively, each respective axis 292 may be at an angle to each other, such as 1° to 80°, for example 1° to 30°, and each respective axis 297 may be at an angle to each other, such as 1° to 80°, for example 1° to 30°. 30°.

The corresponding openings may be angled (such as the perforations 291 shown in FIG. 2B ), with the openings having an angle of 1° to 80°, such as 1° to 30°. The axis 292 of the opening of the through hole 291 and the axis 297 of the opening of the through hole 296 may be perpendicular or substantially perpendicular to the surface of the substrate 217 . Alternatively, axis 292 and axis 297 may form an included angle with the substrate surface, such as less than 5°.

2C shows a partial cross-sectional view of process chamber 200 and showerhead 225 with precursor flow 295 from interior space 294 through perforations 296 into process region 233 . An alternative embodiment is also shown, showing two through holes 296 with axes 297 and 297' at an angle to each other.

FIG. 3A shows a top perspective view of gas distribution assembly 300 . In use, the gas distribution assembly 300 has a generally horizontal orientation such that the axes of the gas perforations formed therebetween are perpendicular or generally perpendicular to the plane of the substrate support (see substrate support 265 in FIG. 2A ). FIG. 3B shows a bottom perspective view of gas distribution assembly 300 . FIG. 3C is a bottom view of gas distribution assembly 300 . 3D is a cross-sectional view of the gas distribution assembly 300 taken along line 3D-3D of FIG. 3C. 3E is a cross-sectional view of the bottom plate 325 of the gas distribution assembly 300 along line 3E-3E of FIG. 3C. 3F and 3G are enlarged views of the features of the bottom plate 325 . FIG. 3H is a bottom view of upper plate 320 of gas distribution assembly 300 . FIG. 3H' is a cross-sectional view of the upper plate 320 along line 3H'-3H' of FIG. 3H. Figure 3H" is a bottom perspective view of upper plate 320. Figures 3I and 3I' are enlarged views of features of upper plate 320. Figure 3J is a top view of annular body 340 of gas distribution assembly 300. Figure 3K shows the bottom of annular body 340 , wherein the annular body 340 has a heating member 327 disposed therein. FIG. 3L is a partially enlarged view of the gas distribution assembly 300 of FIG. 3D. FIG. 3M is a cross-sectional view of the annular body 340 along the line 3M-3M of FIG. 3J .

Referring to FIGS. 3A-M , the gas distribution assembly 300 generally includes an annular body 340 , an upper plate 320 and a bottom plate 325 . The annular body 340 is an annular ring having an inner annular wall 301, an inner lip 302 (which extends radially outward from the inner annular wall 301), an upper recess 303, a seat 304 and an outer wall 305, as shown in particular in FIG. 3L . The annular body 340 has a top surface 315 and a bottom surface 310 defining a thickness of the annular body 340 . Conduits 350 may be formed in top surface 315 and fluidly connect cooling channels 356 (which may also be formed in top surface 315 ), as shown in FIG. 3A . Conduit 355 may be formed in bottom surface 310 and fluidly connect cooling channel 357 (which may also be formed in bottom surface 310 ), as shown in FIG. 3B . The cooling channels 356, 357 may be adapted to allow cooling fluid to flow therethrough. A heater recess 342 may be formed in the bottom surface 310 and adapted to hold the heating member 327, as shown in FIG. 3K.

The upper plate 320 is a disc-shaped body having a plurality of first perforations 360 formed therebetween, the disc-shaped body having a diameter selected to match the diameter of the upper recess 303, as shown in particular in Figures 3D and 3H-I'. The first perforations 360 may extend beyond the bottom surface 306 of the upper plate 320 to form a plurality of raised cylindrical bodies 307 . Between each raised cylindrical body 307 is a gap 395 . As shown in Figures 3H and 3H", the first perforations 360 are arranged in a polygonal pattern on the upper plate 320 such that imaginary lines passing through the centers of the outermost first perforations 360 define a dodecagon. The characteristics of this pattern can also be In a staggered column arrangement (such as 15-25 columns, eg 21 columns) of 5-60 columns of first perforations 360. Each column has 5-20 first perforations 360 (such as 6-18 perforations) along the y-axis , and each column is separated by 0.4-0.7 inches (such as about 0.54 inches). Each first perforation 360 in a column can be translated along the x-axis from the previous first perforation by each corresponding diameter of 0.4-0.8 inches (such as about 0.63 inches). The first perforations 360 are staggered along the x-axis from the perforations in another row by each corresponding diameter by 0.2-0.4 inches (such as about 0.32 inches). In each row, the first perforations 360 may be equally spaced from each other Separation. In the configuration shown, there are a total of 312 first perforations 360. It will be appreciated that other hole patterns may be used.

At the center of the upper plate 360, instead of the first perforation 360, there is a protrusion 308, as shown in Figure 3I'. The protrusion 308 extends to the same height as the raised cylindrical body 307 .

Bottom plate 325 is a disc-shaped body having a plurality of second and third perforations 365, 375 formed therebetween, the disc-shaped body having a diameter selected to match the diameter of upper recess 303, as shown in particular in FIGS. 3C and 3E-G. Base plate 325 has a uniform thickness of about 0.1-0.2 inches, such as about 0.15 inches, and has a diameter that matches the diameter of inner annular wall 301 of annular body 340 . The second perforations 365 are arranged in a pattern that aligns with the pattern of the first perforations 360, as previously described. In an embodiment, when the upper plate 320 and the bottom plate 325 are disposed one on top of the other, the axes of the first through hole 360 and the second through hole 365 are aligned. The plurality of first through holes 360 and the plurality of second through holes 365 may have their respective axes parallel or substantially parallel to each other, for example the through holes 360, 365 may be concentric. Alternatively, the plurality of first through holes 360 and the plurality of second through holes 365 may make the corresponding axes be arranged at an angle of 1° to 30° with each other. At the center of the bottom plate 325, there is no second perforation 365, as shown in FIG. 3F.

The plurality of second through holes 365 and the plurality of third through holes 375 form alternate staggered columns. These third perforations 375 are arranged between at least two second perforations 365 of the bottom plate 325 . Between each of the second through holes 365 there is a third through hole 375 equally spaced between the two second through holes 365 . There are also six third perforations 375 disposed around the center of the bottom plate 325 in a hexagonal pattern. No third through hole 375 is provided at the center of the bottom plate 325 . There are also no third perforations 375 disposed between the peripheral second perforations 365 that form vertices of the polygonal pattern of these second perforations. A total of 876 third through holes 375 are formed through the bottom plate 325 .

The first, second and third apertures 360, 365, 375 are all adapted to allow fluid to pass therethrough. The first and second perforations 360, 365 may have cylindrical shapes, and alternatively may have varying cross-sectional shapes including conical, cylindrical, or combinations of shapes. In an example, the first and second perforations 360, 365 may have a diameter of about 0.125 inches to about 0.5 inches, such as about 0.25 inches. Alternatively, the second through hole 365 may have a diameter equal to or greater than that of the first through hole 360 .

The third perforation may have an hourglass shape, as shown in Figure 3G. The third perforation may have a contour or shape that defines a first cylindrical section 376 (nozzle) having a first diameter of 0.2-0.3 inches, such as about 0.25 inches. The first cylindrical section 376 has an inlet at the end. The first cylindrical section 376 may have a height of about 0.1-0.12 inches, such as about 0.11 inches. The second cylindrical section 378 (throat) has a second diameter smaller than the first diameter and is connected to the first cylindrical section 376 by a transition section 377 . The second diameter may be 0.01-0.03 inches, such as 0.016 inches, or a ratio of the first diameter to the second diameter of about 30:1 to 6:1 (such as about 16:1). The second cylindrical section 378 may have a height of about 0.01-0.02 inches, such as about 0.017 inches. The transition section 377 tapers from the first section 376 and the first diameter at an angle of about 120° to the second section 378 and the second diameter. Transition section 377 may have a height of about 0.1-0.12 inches, such as about 0.11 inches. The third section 374 (diffuser) is connected to the second cylindrical section 378 . The third section 374 can have a conical shape that diverges from the second cylindrical section 378 to the outlet with a height of 0.2-0.3 inches, such as 0.25 inches, and can have a diameter that is larger than the second diameter and smaller than the first diameter. the outlet diameter. The third diameter may be 0.05-0.08 inches, such as 0.06 inches. Alternatively, each of the plurality of third through holes may have a conical shape and have a diameter equal to or greater than that of the plurality of first through holes 360 .

Referring to FIGS. 3J and 3M , the annular body 340 may have a plurality of fluid delivery channels 380 formed radially inwardly into the upper recess 303 relative to the cooling channels 356 , 357 . These fluid delivery channels 380 may be fluidly connected to conduit 372 . The fluid delivery channels 380 may also be fluidly connected to a plurality of fluid conduits 381 formed radially inwardly relative to the fluid delivery channels 380 into the upper recess 303 .

As mentioned above, the gas distribution assembly 300 is generally composed of the annular body 340 , the upper plate 320 and the bottom plate 325 . The upper plate 320 is disposed in the upper recess 303, while the raised cylindrical body 307 faces the bottom plate 310 of the annular body 340, as shown in FIG. 3L. Next, the bottom plate 325 is disposed on the seat 304 and is rotatably oriented such that the axes of the first and second through-holes 360, 365 are aligned, as shown in FIG. 3L. The upper plate 320 is sealingly connected to the bottom plate 325 to fluidly isolate the first and second apertures 360 , 365 and the third aperture 375 . For example, upper plate 320 may be brazed to bottom plate 325 such that a seal is established between the surface of raised cylindrical body 307 and the surface of bottom plate 325 . Next, the upper plate 320 and the bottom plate 325 are electron beam welded to the annular body 340 . The upper plate 320 is electron beam welded such that a seal is established between the outer edge 311 of the annular body and the inner edge 312 of the upper recess 303 . The bottom plate 325 is electron beam welded such that a seal is established between the outer edge 313 of the annular body and the inner annular wall 301 . Fluid can flow through the first and second apertures 360 , 365 along the flow path F ₁ . Fluid can also flow through the conduit 372 , into the fluid delivery channel 380 , through the fluid conduit 381 , through the gap 395 , and through the third through hole 375 along the flow path F ₂ , respectively. Flowing the fluid along two separate flow paths F ₁ , F ₂ ensures the reaction of the fluid after exiting the gas distribution assembly 300 which helps avoid accumulation of material within the gas distribution assembly 300 .

4A-4H, an embodiment of a gas distribution assembly 400 or showerhead is provided, the gas distribution assembly 400 includes a first or upper manifold 410 and a second or bottom manifold 415, and the top of the second manifold 415 is adapted to be connected to The bottom of the first manifold 410 . In use, the showerhead 400 is oriented relative to the substrate such that the axes of any perforations formed in the showerhead are perpendicular or substantially perpendicular to the plane of the substrate.

FIG. 4A shows a perspective view of the top of a showerhead including a first manifold 410 , and FIG. 4B shows a perspective view of the bottom of a showerhead including a second manifold 415 . Figure 4C shows a bottom view of the second manifold. Figure 4D shows a side view of the showerhead along line 4D of Figure 4C. Figure 4D' is a side view of an embodiment of a first perforation. Figure 4E is a side view of the circular plate of the second manifold. FIG. 4F is a side view of an embodiment of the third perforation of FIG. 4E. 4G is a side view of an embodiment of the second and third perforations of FIG. 4E. Figure 4H is a top view of the first manifold and does not show the circular plate with perforations. Figure 4I is a top view of a bottom manifold with a circular plate with a perforation pattern as described herein and without the circular plate.

The first manifold 410 includes an inner circular plate 420 disposed in an outer frame 440 . A transverse duct 450 is formed in the outer frame 440 .

4A and 4B, the inner circular plate 420 has a plurality of first perforations 460 formed in the pattern portion 470, and these perforations are adapted to pass fluid therethrough. The pattern portion 470 may comprise an arrangement of 15-25 columns in staggered columns (eg, 19 columns). Each column has 2-20 perforations 360 (such as 4-17 perforations) along the y-axis, and each column is 0.4-0.7 inches apart (eg, about 0.54 inches). Each perforation in a column may be translated 0.4-0.8 inches (such as about 0.63 inches) from the previous perforation along the x-axis by each respective diameter. The perforations are staggered along the x-axis by 0.2-0.4 inches (such as about 0.31 inches) from the perforations in another column by each respective diameter. In each column, the perforations may be equally spaced from each other.

Each first through hole 460 may have a conical entrance portion that tapers to a first cylindrical portion. In an example, perforation 460 may have an inlet diameter of about 0.2 inches to about 0.5 inches (such as about 0.35 inches), which tapers at about 90° to a first cylindrical portion of 0.125-0.4 inches (eg, about 0.25 inches ). Perforations 460 extend through the circular plate to provide passages for fluid to pass through. The combined height of the first perforations is 0.05-0.15 inches, and the conical entrance portion tapering to the first cylindrical portion may be of equal height. The patterned portion of the circular plate may vary depending on the size of the circular plate and may be at a diameter of about 0.5 inches to about 6 inches for a circular plate having a diameter of about 14 inches.

4B, 4E, 4F, 4G, 4H, and 4I, the inner circular plate 425 has a plurality of second perforations 465 formed in the pattern portion 485, and these second perforations are adapted to pass fluid therethrough. The inner circular plate also has a plurality of third perforations 475 formed in the patterned portion 485, and these third perforations are adapted to allow gas to be introduced into the showerhead through fluid conduits into the process chamber in which the showerhead is disposed. The circular plate has a thickness of about 0.1-0.2 inches, such as about 0.15 inches.

4H, the first manifold 415 is surrounded by a plurality of fluid delivery channels 480 formed in the frame 440, the fluid delivery channels 480 are in fluid communication with the third perforation 475 and are in fluid communication with the second fluid source inlet 490, wherein the second The fluid source inlet 490 is adapted to allow fluid to enter the showerhead from an external source. The second manifold 415 includes an inner circular plate 425 disposed within an outer frame 445 .

The plurality of second through-holes 465 of the second manifold may be aligned with the plurality of first through-holes. The plurality of first through holes 460 and the plurality of second through holes 465 may have respective axes, and the respective axes are parallel or substantially parallel to each other. Alternatively, the plurality of first through holes 460 and the plurality of second through holes 465 may have respective axes, and the respective axes are arranged at an angle of 1° to 30° to each other.

The pattern portion 485 may comprise an arrangement of 15-25 columns in staggered columns (eg, 19 columns). Each column has 2-20 perforations (such as 4-17 perforations) along the y-axis, and each column is 0.4-0.7 inches apart (eg, about 0.54 inches). Each perforation in a column may be translated 0.4-0.8 inches (such as about 0.63 inches) from the previous perforation along the x-axis by each respective diameter. The perforations are staggered along the x-axis by 0.2-0.4 inches (such as about 0.31 inches) from the perforations in another column by each respective diameter. In each column, the perforations may be equally spaced from each other.

Each second perforation 465 may have a second cylindrical portion connected to a conical outlet portion that expands to an open end. In an example, the perforation 465 may have a second cylindrical portion diameter of 0.125 inches to 0.4 inches, such as about 0.25 inches, and an exit diameter of about 0.2 inches to about 0.5 inches, such as about 0.40 inches, at about 40° from The second cylindrical portion tapers. Perforation 465 may have a diameter equal to or greater than perforation 460 . Perforations 465 extend through the circular plate for fluid to pass therethrough. The combined height of the first perforations is 0.05-0.15 inches, such as about 0.35 inches. The patterned portion of the circular plate may vary depending on the size of the circular plate and may be at a diameter of about 0.5 inches to about 6 inches for a circular plate having a diameter of about 14 inches.

The pattern part 485 may have a plurality of third through holes arranged in staggered columns of 30-45 columns (for example, 37 columns). Each column has 2-30 third perforations (such as 3-17 perforations) along the y-axis, and each column is 0.2-0.35 inches apart (eg, about 0.31 inches). Every other column may be disposed along the same x-axis as the second perforations, and the third perforations may be in an alternating order with the second perforations along the x-axis. For columns with only tertiary perforations, each third perforation in the column may be translated along the x-axis from the previous third perforation by each respective diameter of 0.4-0.8 inches (such as about 0.31 inches). For columns with only tertiary perforations, each tertiary perforation in the column may be translated along the x-axis from the previous second perforation by 0.4-0.8 inches (such as about 0.31 inches) by each respective diameter. The third perforations are staggered along the x-axis from third perforations in another column by 0.1-0.2 inches (such as about 0.16 inches) from each respective diameter. In each column, the perforations may be equally spaced from each other.

Referring to Figure 4G, the third perforation may have a contour, or define the shape of a first cylindrical portion 476 (nozzle) having a first diameter of 0.2-0.3 inches, such as about 0.25 inches. The first cylindrical portion has an inlet at one end. The first cylindrical portion may have a height of about 0.1-0.16 inches, such as about 0.14 inches. The second cylindrical portion 478 is connected to the first cylindrical portion 476 by a transition section 477, the second cylindrical portion 478 having a second diameter smaller than the first diameter. The second diameter may be 0.04-0.07 inches, such as 0.06 inches, or a ratio of the first diameter to the second diameter of about 7.5:1 to 3:1, such as about 4:1. The second cylindrical portion may have a height of about 0.01-0.1 inches, such as about 0.05 inches. The transition section 477 tapers from a first section and first diameter at an angle of about 40° to a second section and a first major diameter greater than 0.07-0.1 inches (eg, about 0.08 inches). The first major diameter is larger than the second diameter.

The third cylindrical portion 444 (throat) is connected to the second cylindrical portion 478 and may have a third diameter of 0.01-0.03 inches (such as 0.016 inches) or a first diameter to second diameter of about 30:1 to 6:1. A ratio of three diameters (such as about 16:1). The third cylindrical portion may have a height of about 0.01-0.03 inches, such as about 0.025 inches. A fourth cylindrical portion 479 (diffuser) is connected to the third cylindrical portion 444 . The fourth cylindrical portion may have a diameter similar to the second cylindrical portion 478, but have a fourth diameter smaller than the first diameter. The fourth diameter may be 0.04-0.07 inches, such as 0.06 inches, or a ratio of the first diameter to the second diameter of about 7.5:1 to 3:1, such as about 4:1. The fourth diameter may have a height of about 0.01-0.5 inches, such as about 0.025 inches.

4E-4H, a first fluid, such as a process gas, flows _F1 through the showerhead via a first perforation 460 in the upper manifold and a second perforation 465 in the lower manifold before entering the process area. A second fluid (such as a precursor) flows through channel 490 to gas distribution channel 480 to the interior region 495 between the upper and lower manifolds and flows _F2 to the process area (which is the isolation surrounding the first and second perforations). flow path) and exit through the third perforation 475. Both the first fluid and the second fluid are isolated from each other in the spray head until delivered into the process area.

5A-5F, an embodiment of a gas distribution assembly 500 or showerhead is provided, the gas distribution assembly 500 includes a first or upper manifold 510, a second or central manifold 520 connected to the bottom of the first manifold 510, and a connecting A third or bottom manifold 530 to the bottom of the second manifold 520 . In use, the showerhead 500 is oriented relative to the substrate such that the axes of any perforations formed in the showerhead are perpendicular or substantially perpendicular to the plane of the substrate.

FIG. 5A shows a perspective view of the first manifold 510 , the second manifold 515 and the third manifold 520 . Figure 5B shows a top view of the upper manifold. Figure 5C shows a top view of the central manifold. Figure 5D shows a perspective view of the top of the bottom manifold. FIG. 5E shows a cut perspective view of the first manifold 510 , the second manifold 515 and the third manifold 520 . Figure 5F shows an enlarged portion of the cut perspective view of Figure 5E.

5A and 5B, the upper manifold 510 may have a patterned portion 516 with a plurality of first through holes 511 and a plurality of second through holes 514 formed concentrically around the upper manifold. A plurality of first radial rows 512 arranged in the central portion 513 of the center portion 513, the second through holes 514 are concentrically arranged around the plurality of first through holes 511 and these second through holes 514 are formed into a plurality of second radial rows 515 .

The plurality of first perforations 511 may comprise a plurality of first radial rows 512 (such as 2-24 perforations) of two or more perforations (such as 2-10 perforations, for example about 4 perforations in each radial row). columns, such as 16 columns). The concentric radial rows may be equally spaced from each other at equal angles. In each radial row, the perforations may be equally spaced from each other. Each perforation may have a cylindrical shape in a circular plate. In an example, the first perforation 511 may have a diameter of about 0.1 inches to about 0.5 inches, such as about 0.2 inches, and extend through the circular plate to provide for passage of fluid therethrough.

The plurality of second perforations 514 disposed concentrically about the plurality of first perforations 511 may comprise two or more perforations (such as 2-10 perforations in each radial row, for example about 5 perforations) A plurality of second radial rows 515 (such as 3-40 rows, eg 32 rows). The concentric radial rows may be equally spaced from each other at equal angles. In each radial row, the second perforations may be equally spaced from each other. Each second perforation may have a cylindrical shape in the circular plate. In an example, the second perforation 514 may have a diameter of about 0.1 inches to about 0.5 inches, such as about 0.2 inches, and extend through the circular plate to provide for passage of fluid therethrough.

A back channel 518 (shown in phantom in FIG. 5B ) may be formed on the backside of the upper manifold 510 for delivering gas to the central gap 519 (also shown in phantom). The backside channel provides a second fluid from an external source to the center gap, the second fluid is delivered to the center of the bottom manifold via a central perforation of the center manifold, a plurality of inner gas channels are fluidly connected to the center of the bottom manifold and are provided via the gas perforations in the channel for fluid communication to the process area.

5A and 5C, the central manifold 520 may have a patterned portion 526 with a plurality of first openings 521 and a plurality of second openings 524 formed around the center of the central manifold. The second openings 524 are formed as concentric circles arranged around the plurality of first openings 521 concentrically.

These first openings 521 may be formed in a triangular or pear shape. The shape may comprise an initial side located adjacent the center of the manifold and diverging to a peripheral portion at an angle of 5° to 45°, eg 22.5°. The shape of the peripheral portion may be rounded or flat. The first openings 521 may include 2-24 openings, such as 16 openings. Each first opening 521 may be arranged to correspond to one of the first radial rows 512 . Each opening 521 may be adapted to be of sufficient size to provide an opening around all of the perforations of each respective first radial row. The first openings 521 may be equally spaced from each other at equal angles.

These second openings 524 may be formed in a triangular or pear shape. The shape may include an initial side adjacent to the plurality of first openings 521 and diverging to a peripheral portion at an angle of 5° to 45° (eg, 11.25°). In embodiments of the second openings, the second openings may have about half the divergence angle of the first openings. The shape of the peripheral portion may be rounded or flat. The second openings 524 may include 4-48 openings, such as 32 openings. Each second opening 524 may be arranged to correspond to one of the second radial rows 515 . Each second opening 524 may be adapted to be of sufficient size to provide an opening around all of the perforations of each respective second radial row. The second openings 524 may be equally spaced from each other at equal angles. The second openings may be provided in a ratio of the first openings to the second openings of 1:1 to 1:3, eg 1:2. In an example, the central manifold contains 16 first openings that diverge at an angle of 22.5° and 32 second openings that diverge at an angle of 11.25°.

The center portion 523 of the center manifold may contain perforations that allow fluid communication from the back center of the upper manifold to the center 533 of the bottom manifold.

5A and 5D, the bottom manifold 530 can have a patterned portion 536 with a plurality of first openings 531, a plurality of first gas channels 537, a plurality of second openings 534, a plurality of second gas channels 538 and channel network 539, the first openings 531 are formed as concentric circles arranged around the central portion 533 of the bottom manifold, the first gas channels 537 are arranged between the first openings 531, the second The openings 534 are formed as concentric circles arranged concentrically around the plurality of first openings 531, the second gas passages 538 are disposed between the plurality of second openings 534, and the channel network 539 concentrically surrounds the plurality of openings 531. A second gas channel 538 and the plurality of second openings 534 are provided.

A gas channel network 539 is fluidly connected to the plurality of second gas channels 538 and may be fluidly isolated from the second openings 534 . The plurality of first gas channels 537 may be fluidly connected to the central portion 533 and may be fluidly isolated from the first openings 531 . The first fluid channels 537 may be isolated from the second fluid channels 538 . These first fluid channels include perforations 542 for delivering fluid to the process area.

These first openings 531 may be formed in a triangular or pear shape. The shape may comprise an initial side located adjacent the center of the manifold and diverging to a peripheral portion at an angle of 5° to 45°, eg 22.5°. The shape of the peripheral portion may be rounded or flat. The first openings 531 may include 2-24 openings, such as 16 openings. Each first opening 531 may be provided to correspond to one of the first openings 521 of the central manifold. Each opening 531 may also be adapted to be of sufficient size to provide an opening around all of the perforations of each respective first radial row of the upper manifold. The first openings 531 may be equally spaced from each other at equal angles.

These second openings 534 may be formed in a triangular or pear shape. The shape may include an initial side located adjacent to the plurality of first openings 531 and diverging to a peripheral portion at an angle of 5° to 45° (eg, 11.25°). In an embodiment of the second opening 531, the second opening may have about half the divergence angle of the first openings. The shape of the peripheral portion may be rounded or flat. The second openings 534 may include 4-48 openings, such as 32 openings. Each second opening 534 may be positioned to correspond to one of the second openings 524 of the central manifold. Each second opening 534 may be adapted to be of sufficient size to provide an opening around all of the perforations of each respective second radial column of the upper manifold. The second openings 534 may be equally spaced from each other at equal angles. The second openings 534 may be provided such that the ratio of the first openings 531 to the second openings 534 is 1:1 to 1:3, eg 1:2. In an example, the central manifold contains 16 first openings that diverge at an angle of 22.5° and 32 second openings that diverge at an angle of 11.25°.

The plurality of first gas channels 537 are disposed between the plurality of first openings 531 , and may have the same number of first gas channels 537 as the number of the first openings 531 . The gas channels have an inner portion connectable to the central portion 533 of the manifold, an outer portion expandable with the first openings 531 , and have a substantially rectangular or square cross-section. Each first gas channel has one or more perforations, outlets formed in one or more rows at the bottom of the first gas channel to provide fluid communication to the process chamber. For example, each first gas channel has 2 rows of 10 perforations, each row has 5 perforations. The plurality of first gas channels 537 are adapted to contact the bottom surface of the central manifold, forming sealed channels, and isolated from the openings 521 , 524 of the central manifold.

The plurality of second gas passages 538 are disposed between the plurality of second openings 534 , and may have the same number of second gas passages 538 as the number of the second openings 534 . The gas channels have interiors expandable with the interiors of the second openings, exteriors connected to the channel network 539, and have a generally rectangular or square cross-section. Each second gas channel has one or more perforations, outlets, formed in one or more columns at the bottom of the second gas channel to provide fluid communication with the process chamber. By way of example, each second gas channel has 2 rows of 10 perforations, each row having 5 perforations. The plurality of second gas channels 538 are adapted to contact the bottom surface of the central manifold, forming sealed channels, and isolated from the openings 521 , 524 of the central manifold. The plurality of first gas channels 537 and the plurality of second gas channels 538 may be fluidly isolated from each other.

A channel network 539 is disposed concentrically around the plurality of second gas channels 538 and the plurality of second openings 534 and is fluidly connected to the second gas channels 538 . In the bottom manifold embodiment, each second gas channel 538 is connected to a channel network 539 . The channel provides the second fluid to the showerhead for delivery to the process area of the process chamber. The second fluid flowing to the channel network may be the same as or different from the second fluid provided to the plurality of first gas channels 537 via channels 518 .

Referring to Figures 5E and 5F, a first fluid (such as a process gas) passes through a second perforation 514 in the upper manifold, a second opening 524 in the center manifold, and a second opening 534 in the bottom manifold before entering the process area 550. Flow _F3 is passed through the spray head. A second fluid (such as a precursor) flows F through channel 518 to center 519, through center 523 of _the center manifold to center 533 of the bottom manifold, through one or more first gas channels 537 and perforations 542, and/or The second fluid (or third fluid) flows through channel network 539 to one or more second gas channels 538 and is delivered to the process area via perforations 542 . Both the first fluid and the second fluid are isolated from each other in the spray head until delivered into the process area.

Embodiments described herein allow two different fluids, such as gases, to be delivered to a process area without mixing until directly above the surface of the substrate. The thermal control aspects provided herein also allow the temperature of the various gases provided to the process area to be controlled. This improves control of processes within the chamber, such as deposition, etch processes, and the like. For example, gas mixing can be controlled such that reactions in the process area can be increased. Undesirable deposition and particle generation on chamber components can be minimized. This increases throughput by reducing particulates and minimizing downtime for chamber cleaning.

It is believed that a dual zone gas showerhead as described herein allows separate process gases to be introduced into the process chamber to avoid any undesired gas reaction and mixing prior to entering the process chamber. Dual zone showerheads provide better uniform gas distribution with independent gas introduction and control at the center and edges of the showerhead.

In alternative embodiments, the precursors may be introduced into the interior space through more than one gas independent channel. The plurality of perforations to regulate the flow of the first fluid from the first process region (such as 215) to the second process region (such as 233) and the plurality of perforations to regulate the flow of the precursor may be adapted to provide any structure necessary to provide a central to Multiple zone flow control at the edge. In such designs, precursor and top flows are introduced from both the center and the edge (or even multiple regions), which can be controlled separately to control the final deposition profile. For example, limiting the number of perforations in the region over the exterior of the substrate to direct flow over the center portion of the substrate. Under the dual-zone showerhead structure, the precursor injection can be divided into two or more zones in the radial direction, and each zone has independent flow control.

In addition, the present invention may include symmetrical pumping pads with symmetrical separation from chamber to frontline (first stage channel has one port and connects to second stage with two ports; each second stage port connects to Two ports on the third stage, and so on, to the final pumping hole connected to the chamber). The final channel can be separated into multiple different blocks or can be concatenated channels. It can be varied by omitting one or more stages, eg from 4 to 32 etc., but still maintaining uniform pumping from the chamber by optimizing the pumping hole size (bore diameter and channel length). The liner also removes the gap between the liner and the C-groove, reducing the effect of the slot opening.

While the foregoing is directed to embodiments of the invention, other and further embodiments of the invention may be devised without departing from the essential scope of the invention, which is defined by the following claims.

Claims (5)

1. A gas distribution assembly comprising: upper manifold, which contains: a first plurality of perforations formed in a first plurality of radial rows concentrically disposed about a central portion of the upper manifold; and a plurality of second perforations disposed concentrically around the plurality of first perforations and formed as a plurality of second radial rows, wherein the plurality of second perforations are disposed on the periphery of the first radial rows ; a center manifold that connects to the upper manifold and contains: a plurality of first openings disposed concentrically about a central portion of the central manifold; and a plurality of second openings disposed concentrically about the plurality of first openings of the central manifold; and a bottom manifold that connects to the center manifold and contains: a plurality of first openings disposed concentrically about a central portion of the bottom manifold; a plurality of second openings disposed concentrically about the plurality of first openings of the bottom manifold; a plurality of second gas channels disposed between each of the plurality of second openings on the upper side of the bottom manifold; and a network of channels disposed concentrically about the plurality of second openings of the bottom manifold and fluidly connected to one or more of the plurality of second gas channels, wherein each of the plurality of first openings of the central manifold is configured to correspond to one of the plurality of first radial columns, and each of the plurality of second openings of the central manifold is configured to each of the plurality of first openings of the bottom manifold is disposed corresponding to one of the plurality of first openings of the central manifold , each of the plurality of second openings of the bottom manifold is arranged to correspond to one of the plurality of second openings of the central manifold, and the plurality of second gas channels are adapted to contact the The bottom surface of the central manifold forms a sealed channel and is isolated from the first opening and the second opening of the central manifold. 2. The gas distribution assembly of claim 1 , wherein each of the plurality of second gas channels further comprises one or more perforations disposed in the second gas channels and formed through the bottom manifold. 3. The gas distribution assembly of claim 1, further comprising a plurality of first gas channels disposed between each of the first plurality of openings on the upper side of the bottom manifold. 4. The gas distribution assembly of claim 1, further comprising: a dorsal channel, wherein the dorsal channel provides fluid from an external source to the central gap, the fluid is delivered to the center of the bottom manifold via the central perforation of the central manifold, wherein a plurality of inner gas channels are in fluid communication to the center of the bottom manifold and is in fluid communication to a process area via perforations disposed in the plurality of inner gas channels. 5. The gas distribution assembly of claim 3, wherein each of the plurality of first gas channels further comprises one or more perforations disposed in the first gas channels and formed through the bottom manifold.